The present invention relates to integrated circuits, and more specifically to a circuit and method for determining the operating performance of an integrated circuit.
Clocked integrated circuits, in particular, microprocessors, have maximum frequencies which are dependent on many factors. Such factors include processing load, transistor junction temperature, and applied bias voltages. Normally, all of these factors are considered when developing a specification based upon a predetermined maximum frequency. The predetermined maximum frequency is typically chosen as a "worst" case, i.e., when all of the factors are present.
In some specifications, special sorting and tighter temperature and voltage ranges are prescribed to squeeze a higher level of performance out of an integrated circuit meeting the specification. However, integrated circuits produced by such approaches are prone to failure, since the ranges are easily exceeded.
Therefore, it would be desirable to provide a circuit and method for determining the operating performance of integrated circuits and for indicating such performance degradation. It would also be desirable to provide a circuit and method which automatically vary the operating frequency of an integrated circuit to an optimal level. Such a circuit would reduce the operating frequency before limits are exceeded.